On Wed, Aug 5, 2015 at 11:11 AM, Bowie Bailey <Bowie_Bailey@xxxxxxx> wrote:
> On 8/5/2015 1:00 PM, Chris Murphy wrote:
>>
>> On Wed, Aug 5, 2015 at 10:52 AM, Bowie Bailey <Bowie_Bailey@xxxxxxx>
>> wrote:
>>>
>>> How would I go about pointing it at the partition?
>>>
>>> What I am currently doing is this:
>>> device (hd0) /dev/hdg
>>> root (hd0,0)
>>> setup (hd0)
>>
>>
>> setup (hd1,0)
>>
>> It's hd1 if your device map is correct and hdg is hd1. And then ,0 is
>> for the first partition assuming that's an ext3 boot partition.
>
>
> What I am doing on my other system (where everything is working), is forcing
> grub to install to both drives as hd0. I found that when the first drive
> dies and I remove it from the system, grub will see the remaining drive as
> hd0, regardless of what it was before. So if I install grub to the second
> disk as hd1, then it won't boot as a single drive.
Nothing about hd0 or hd1 gets baked into the bootloader code. It's an
absolute reference to a physical drive at the moment in time the
command is made. If there is only one drive connected when you
initiate this command, then it's hd0. Almost invariably hd0 is the
current boot drive, or at least it's the first drive as enumerated by
the BIOS.
So long as the drive in question gets a bootloader, it'll boot
regardless of what hdX designation it takes. I'm just not totally
convinced the designation is correct here because I really don't see
how 'setup hd0' works on a drive that has no MBR gap.
>
> And to get this back to a single thread:
>
> On 8/5/2015 1:03 PM, Chris Murphy wrote:
>>
>> On Wed, Aug 5, 2015 at 10:58 AM, Bowie Bailey <Bowie_Bailey@xxxxxxx>
>> wrote:
>>
>>> I tried 'smartctl -a' and 'hdparm -I', but I don't see anything about
>>> Advanced Format. What am I looking for?
>>
>> # smartctl -i /dev/hdg | grep -i sector
>> Sector Size: 512 bytes logical/physical
>
>
> I don't get a "Sector Size" line.
>
> smartctl version 5.38 [i686-redhat-linux-gnu] Copyright (C) 2002-8 Bruce
OK that version predates sector size info. See if your version of
hdparm will do it:
# hdparm -I /dev/hdg | grep -i sector
That spits out several lines for me, including
Physical Sector size: 512 bytes
Another one is:
# parted -l /dev/hdg | grep -i sector
I'm willing to bet that physical sector size is 4096 bytes
> Allen
> Home page is http://smartmontools.sourceforge.net/
>
> === START OF INFORMATION SECTION ===
> Device Model: WDC WD10EZEX-60M2NA0
I looked this up and found this:
http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771436.pdf
That lists the 1TB as being advanced format. If that's the correct
spec sheet then the next question is what is the workload for this
drive? If it's just a boot drive and performance is not a
consideration then you can leave it alone, the drive firmware will do
RWM internally for the wrong alignment. But if performance is
important (file sharing, database stuff, small file writes including
web server), then this needs to get fixed...
--
Chris Murphy
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